There is growing interest in entrepreneurs who have been involved in more than one venture, yet to date there has been relatively little theoretical development and systematic empirical examination of the topic. In particular, there has been little attention to the potential heterogeneity of habitual entrepreneurship. This study aims to contribute to this emerging area in two ways. First, it outlines a conceptual typology of habitual entrepreneurs who have founded, purchased, or inherited businesses. Second, the empirical part of the study focuses on owner-managers, providing an exploratory analysis of the characteristics and effects of independent business ownership by novice, portfolio, and serial founders. Novice founders are those that have no prior entrepreneurial experience as either a founder, an inheritor, or a purchaser of a business. Portfolio founders retain their original business and inherit, establish, and/or purchase another business. Serial founders are those who sell their original business but at a later date inherit, establish, and/or purchase another business. The study derives propositions suggesting differences among the three types of founders. At the individual founder level of analysis, similarities as well as differences in the personal background, work experiences, reasons leading to the start-up of businesses, and personal attitudes to entrepreneurship of these three types of entrepreneurs are explored. At the organizational level of analysis, finance, employment and performance differences among the businesses owned by the three types of entrepreneurs are presented. The issues are examined using a sample of entrepreneurs who were the principal owner-managers of independent businesses in Great Britain. The sample included 389 novice founders (62.6%), 75 portfolio founders (12.1%), and 157 serial founders (25.3%). No statistically significant differences were found among the three groups of entrepreneurs with regard to the main industrial activity, geographical location, and the age of their businesses. Univariate and multivariate tests were used to examine potential differences between the groups. The results of the study show significant differences between portfolio and serial founders with regard to their parental background, work experience, and their age when they started their first business. Differences were also found with respect to reasons leading to start-up, personal attitudes to entrepreneurship, and sources of funds used during the launch period of the surveyed business. These findings suggest that habitual entrepreneurs cannot be treated as a homogeneous group. The analysis, however, failed to find any significant differences between the performance of the surveyed firms owned by habitual founders and novice founders and between the two types of habitual founders. The findings of the study indicate for researchers that there is a need to carefully define the unit of analysis in any examination of entrepreneurs. In particular, there is a need to take note of the heterogeneity of types of entrepreneur and to consider the entrepreneur as the appropriate unit of analysis rather than simply the firm. Although this study focused on habitual founders of businesses, the theoretical section of the study also identified other types of habitual entrepreneurs, such as serial corporate entrepreneurs and serial management buy-out and buy-in cases. These other types of habitual entrepreneurs would appear to warrant further analysis. The findings of this study have a number of implications for practitioners, especially venture capitalists. The absence of significant performance differences between novice and habitual entrepreneurs, which is consistent with the results from other studies, emphasizes the need for venture capitalists screening potential investees not to rely solely on previous experience. The study also has implications for policy-makers, especially with respect to decisions concerning the allocation of resources to assist nascent entrepreneurs, novice entrepreneurs, and habitual entrepreneurs. The similarities in business performance among novice, serial, and portfolio entrepreneurs suggests that policy-makers need to be careful in targeting scarce resources. Most notably, targeting resources to encourage talented nascent entrepreneurs to become novice entrepreneurs may offer returns which are at least as good as targeting resources to more experienced entrepreneurs.